Kirkham leads the series and is 195 points ahead of nearest rival, Callan.
Kirkham was not fazed by Madill sitting behind his wheel in the final at Melba. "I knew that I had the horsepower to get by him," declared Kirkham. "If Luke felt the way I did I don't think he could've come around me."
After fellow Adelaide rider, Sam Willoughby secured the World Cup title this year, Kirkham expects there will be more South Australian riders on the international scene.
"Adelaide has some good riders at the moment. Even with Sam now in the US there is still his brother, Matt and Anthony Dean is back into training too," explained Kirkham. "It's a really good scene at the moment."
Canberra's Caroline Buchanan secured her second win of the weekend by taking out both BMX national series rounds in Canberra yesterday and today. The current national champion was challenged in the final straight by a fast finishing Rachel Bracken from Townsville.
Beijing Olympian, Nicole Callisto from Perth slid out on the final turn leaving Brisbane's Kelly Percy to take third.
Buchanan now takes over the lead in the elite series. Buchanan is well positioned with 504 points while nearest rival, Bracken, is on 376 points.
The final and seventh round will be held in early May in conjunction with the National Championships in Shepparton, Victoria.
Over the next two days the national team will prepare on Luke Madill's Olympic track replica. The team then departs for Madrid to compete in the first World Cup Supercross round at the end of March.